Graphical user interface for a display screen or portion thereof



FIG. 1 is a front view of a graphical user interface for a display screen or portion thereof showing our new design; and,

FIG. 2 is a front view of a second embodiment thereof.

The broken line showing of the elements in FIG. 2, and the the display screen or portion thereof and the text in both figure views is not part of the claimed design. 

The ornamental design for a graphical user interface for a display screen or portion thereof, as shown and described. 